Ferguson attended public schools and the University of Pittsburgh. He graduated from the University of Michigan at Ann Arbor in 1913, was admitted to the bar the same year and commenced practice in Detroit, Michigan.
He was judge of the circuit court for Wayne County, Michigan from 1929–1942 and also professor of law at Detroit College of Law (now part of Michigan State University) from 1929 to 1939. Ferguson was elected as a Republican to the United States Senate in 1942 and was reelected in 1948, serving from January 3, 1943, to January 3, 1955. Ferguson successfully was re-elected in 1948, a year dominated by the Democratic party"s upset wins.
He was an unsuccessful candidate for reelection in 1954, defeated by Democrat Patrick V. McNamara.
While in the Senate, he served as chairman of the Republican Policy Committee in the 83rd United States Congress. In 1948, he served as chairman of the Investigations Subcommittee of the Committee on Expenditures in Executive Departments, which held hearings on such matters as export control violations, for which Soviet spy William Remington was called in to testify.
The trial of Nazi war criminal Ilse Koch. And the Mississippi Democratic Party"s sale of postal jobs, which Mississippians from rural areas attested to purchasing.
He introduced the Senate version of the bill that inserted "under God" into the Pledge of Allegiance in 1954.
Michigan"s 17th congressional district United States House of Representatives Republican Charles G. Oakman had previously introduced a House version. The bill became law on Flag Day, June 14, 1954. Also in 1954, Ferguson proposed several amendments to the Bricker Amendment.
Ferguson served as United States Ambassador to the Philippines from 1955 to 1956 and was judge of the United States Court of Military Appeals at Washington, District of Columbia from 1956 to 1971.
He served as senior judge on the United States Court of Military Appeals from 1971 to 1976. In 1976, he retired and moved back to Michigan and resided in Grosse Pointe until his death.
He is interred in Woodlawn Cemetery, in Detroit. Ferguson"s behind the scenes involvement in influencing the failed investigation, trial, and slander of Preston Tucker by the Securities and Exchange Commission has long been speculated.